Reproduction of music



1 623,968 Apnl 12 1927. w. L. MORRIS v REPRODUCTION OF uusro Filed 'sept. 10, 1924 4 smug-s eet 1 922 zfemar Mmm L 7720mm April .12, 1927.

W. L. MORRI$ REPRODUCTION owmusrc Filed Sept. 10, 1924 4 Sheets-Sheet 2 Q & 522 en to)" pay fir M'Zham L 721017123 pm] 12 w. L. MORRIS REPRODUCTION OF MUSIC Filed Sept. 10, 1924 4 Sheets-Sheet 3 1,623,968 W. L. MORRIS Filed Sept. 10, 1924 4 Sheets-Skies; 4

A ril 12 1927,

c mrentor Illlziam L. 23 I v w my.

Patented Apr. 12, 1927.

UNITED STATES 1,623,968 PATENT oFFicE- WILLIAM L. MORRIS, OF CHICAGO, ILLINOIS, ASSIGNOR TO G'ULBRANSEN COMPANY,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

REPRODUCTION OF MUSIC.

Application filed September 10, 1924. Serial No. 736,814.

My invention relates to the mechanical reproliluction of music, and more specifically to an improved expression mechanism for varying the intensity of different sounds produced by any musical instrument under the automatic control of a perforated note sheet or its equivalent as to the sounds pro duced, with e ther manual. 0. automatic control of intensity.

It is concerned primarily with obtaining more speed in changing from one intensity to aiuither, h the elimination of excessive waste of power; and with obtaining reliable operationof lower intensities than has here- -C' tofore been practicable.

its superiority over prior devices resides especially in an ability to change quickly from low to high pressure, as high pressure is always available to quickly draw from and utilize. although it is also superior in lowering pressure quickly because the vol ume affected by the necessary pressure change is much smaller.

Further objl-icts and advantages, including a wide range of control combined with extreme sensitiveness over the entire range, will become apparentas the description procoeds.

In the accompanying drawings: as liig. 1 is a front elevation indicating more or less di"grammatically the application of the principles of my invention to a player piano;

Fl 2 is a plan view of the expression con- :zo trol mechanism proper, with the cover removed;

l i 3 is a vertical section on line 3-3 of Fig. 2;

llig. 4 a detail section on line 44: of

Fig. 5 is a section substantially on line 5-5 of Fig. 1 of the interconnection between the motor driven and the foot actuated sources of supply; and

Fig. G a section on line 66 of Fig. 5.

in the embodiment of my invention selected for illus ration, the instrument controlled a piano ll), equipped with the 'c stack 11 controlled by open ere board 12. Except that advisable to employ a stack having as small a vohnnetric capacity as possible, any rnitablc or preferred stack may be employed in connection with the invention, and as the details of construction thereof form no part of the n'csent invention, this disclosure has not been icumbered therewith beyond the statement that it has a minimum volumetric ca )acity. Reference is also made to the copending application of Christian Gulbransen, Serial No. 743,866 filed Oct. 16, 1924, for detailed disclosure of a stack of very small volumetric capacity suitable for use in connection with my invention.

Motor 14: actuates two double bellows 16 to withdraw ir from conduit 18. Conduit 18 opens into a chamber 20 communicating through aperture 22, controlled by check valve 24-, with a pneumatic 26 forming part of the storage capacity of the. system. The foot actuated pumping mechanism 28 also exhausts from the same pneumatic 26, the connection being indicated diagrannnatically at 30 in Fig. 5. It will thus be apparent that when the foot actuated pumping mechanism is used, check valve 252, prevents any suction in chamber 20 or conduit. 18.

Referring now to Figs. 1 and 3, the suc tion in pneumatic 26 obtains also in a suitable air passage. 32, which, as will be apparent hereinafter, may he of any desired capacity, so far as the action of the expres sion means is concerned, since nochange in its condition is required for the operation of said mechanism. From passage 32, a conduit 34 leads to the expression mechanism designated as a whole by reference character 36, and from said mechanism conduit 38 delivers the etl ective suction to the pneui'natic stack.

Referring now to Fig. 3, conduit 34L opens into an annular valve chamber 40 housing a suitable valve 42 vertically movable between a lower seat 44 and an upper seat 46.

The valvestem 4S guided longitudinally in sleeve also carries an upper valvecooperating with seat above conduit 38. ent of both valves To secure suitable adjus with their seats when the shear down, the upper valve comp s a slightly resilient diaphragm 5i carrying a valve ring 56. There also a slight clearance at 413 between valve 42 and its stem to let the valve accommodate itself slightly for precise adjustment with its seats. The stem and valves are resiliently urged downward to the position shown in Fig. 2 by a compression spring 58, the tension of which may be suitably adjusted by set screw 60 threaded through the cover 62, and bearing on spring washer 63.

The valve 51 controls communication between conduit 88 and passageway 61 leading to the expression control mechanism proper, and valve 42 connects conduit 34 either to conduit 38 when valve 5 1 is closed or to passageway 66 leading from the expression control mechanism proper. It will be ap parent that in the position shown in Fig. 3, suction is delivered to the stack direct and unmodified by the action of the control mechanism, but that raising stem 18 will force the suction to travel through passageways 66 and 6e and the expression mechanism before reaching the stack.

The position of stem 48 is controlled by a pneumatic 68 connected by a small conduit 70 with the suction producing source. The conduit leads to a valve 7 2 having the valve passage 72 which passage in one position of the valve will connect conduit 70 with conduit 70 leading to duct 18 of the motor pump, and which in another position will connect conduit 70 with conduit 71 leading to duct 30 of the foot pump. Fig. 5 shows pneumatic 68 in connection with duct 18 and the motor pump. lVhen the expression mechanism 36 is desired to be used when the foot pump is employed, valve 72 is turned 90 degrees to disconnect pneumatic 68 from the motor pump and to connect it with the foot pump. ll hen either suction pump is started, as soon as suilicient suction is developed for proper use of the expression mechanism, pneumatic 68 will collapse and shift stem 18 and its valves from the position shown in Fig. 3 to the upper position. The valve 72 may be turned to disconnect the passageway 7 2 from both the ducts 7 0 and 74, in which case the expression mechanism is inoperative during operation of either the foot pump or the motor pump.

\Vhen the motor is operating and the power used in the stack is small, the suction in chamber 20 should be relieved to prevent an excessive and unnecessary load on the pump bellows and associated parts. I have provided a mufller 71 of usual construction and relief valve 73 held seated by adjustable spring '75. It will be noted that turning cock 72 to connect with pipe 74 will connect pneumatic 68 with the foot operated pump, but not chamber 20 or valve 73.

Valves 12 and 51 and the chamber cooperating therewith are located in the body 76 having the top cover 62 and the bottom 7 8. This entire structure is suitably fastened to the side of the main body 80 having the top cover 82 and the bottom cover 8 1. The effective suction delivered through the passageway 66 enters chamber 86 housing a vacuum valve comprisinga body 88, preferably of wood carrying a cap 90 preferably of metal,

having a throttle lip 92 adapted to seat against a suitable receiving washer 94. The lower end of body 88 is connected to the bottom cover 81 by a suitable flexible diaphragm 96.

A central stem 98 passes through the annular body 88 and has threaded thereon at its upper end a head 100, preferably secured against rotation by a pin 102. Below head 160 is a sleeve 101 sliding freely in a hub 106 carried by arms projecting inwardly from cap 90. Suitably mounted on sleeve 101 is a second throttle 108 hereinafter referred to as the atmospheric valve. Below sleeve 101 is a second sleeve 110 held in place by nut 112. Piston 114 is a driving lit on sleeve 110 and moves in a dashpot cylinder 116 having a metal lining 118, the piston being provided with a suitable felt or leather piston ring 120 fitted to slide in lining 118 with the minimum of friction necessary to maintain an approximate seal. The clear ance at 122 around sleeve 110 controls the extent of damping, but it will be obvious that appreciable leakage past ring 120 will do no harm, so that an unusually light cont-act will be entirely satisfactory. Cylinder 116 is spaced from bottom cover 84 by spacer blocks 124, so that the pressure on the under surface of diaphragm 96, body 88 and atmospheric valve 108 is that of the atmosphere.

\Vhen stem 1-8 is raised, the full suction delivered by the source obtains in chamber 86. The weight of the body 88 and cap 90 is such that when this is the case, the upward pressure of the atmosphere on diaphragm 96 and the body will slightly more {than support such weight, so that the throttle tends to close at 92 and entirely out off communication between chamber 86 and passageway 126 leading to passageway 64 and the stack. In the position shown, atmospheric valve 108 is also seated on the throttle body 88, so that passageway 126 and the stack are cut off, both from atmosphere and from the source of suction. The same washer 127 may serve both as a packing for cap 90 and a seat for valve 108. It will be apparent that any upward movement of stem 98 from the position shown would open atmospheric valve 108, to reduce the suction obtaining in the stack, but that any downward nmvement of the same would act through valve 108 to push down the throttle body 88 and exhaust air from the stack into chamber 86. It will thus be apparent that the control of the momentary suction in passage 126 includes two ranges. first when valve 108 is closed and throttle 92 open, and second when throttle 92 is closed and valve 108 opened. These two ranges are mutually exclusive, but the passage from one to the other is a continuous one during a single half oscillation of stem 98 in either direction.

It is essential that stem 98 have the utmost- Inc freedom of movement. For this purpose, clearance is provided at 128 around head 100, and the entire plunger is carried primarily by a bell crank lever having the free end of its horizontal arm pivoted at 132 in a slot in the top of head 100 and its vertical arm in pulled back by spring 136 adjustabh froin outside the body by means of adjusting nut 138. This, and the guidance at forded by piston 11 1, constitute the sole i'nechanitail supporting and guiding means for stem 98 and the parts carried thereby.

By properly proportioning the mass of the moving parts, their natural frequency of vibration can be made different from any other natural frequency of the air spaces or passages. The solid piston 11 1 affords convenient means for doing this.

Under certain rather extreme conditions of movement, it has been found that valve 108 can move down to open throttle 92 and up again so quickly that the opening of valve 108 will bleed the pressure in chamber 8b to such a point that the effective suction will not lift body 88 back to the position shown in Fig. 8. To prevent this pneumatic disconnection of these parts, without interfer ing in any way with the operation thereof, I provide a suitable stop comprising an arm 14:0 bifurcated to straddle stem 98, and carrying pads 1 12 to engage the lower end of body 88 and limit its downward movement. This arm preferably has a fulcrum 14:4, and wood screws 146 on either side of the fulcrum for convenient support and adjustment of the arm. The stop 142 limits the extreme downward displacement of the vacuum *alve, and the clearance between hub 106 and stop washer 14:3 similarly limits the extreme opening of atmospheric valve 108. A rapid change of condition is thereby prevented from throwing the parts farther than they need to go for effective control of the air flow. i It will be apparent that the structure so far described will automatically bias the plunger to a predetermined position depending on the varying tension of spring 136 as the plunger moves up and down. The atmospheric pressure and the suction in chamber 86 being substantially constant during playing operation, any change in the suction in PHSSHQG 126 will disturb this equilibrium and result in moven'ient. Thus, a decrease in the suction in the s wack will let the plunger fall, increasing the clearance below seat 941, which will automatically restore the suction in passageway 126 to the equilibrium value. Similarly, if the suction were too high in passageway 126, the parts would move up to the position shown in Fig. 3, completely stopping the exhaust of air, until the air let into the system by operation of the pneumati s in the stack had cut down the pressure; or in case the discrepancy were even greater, valve 108 would continue to move up beyond the position shown in F 3 and bleed air into the stack to reduce the suction. It will be noted that this will never occur until after valve 92 has cut off communication with chamber 86. It has been found in practice that during normal playing throttle 92 will flutter up and down at varying distances from seat 9 1- in response to mon'ientary changes in suction in the stack due to the playing of one or more notes, and n'iaintain a remarkably constant pressure, or suction, in passageway 126. Thus, when single notes are being played in very rapid succession, the inertia of the partscombined with the damping effect of the dashpot establishes a mean position from which only slight displacements will occur, but when a heavy chord calls for striking a large number of notes at once, the sudden drop in pressure as the pneumatics in the stack collapse will let the throttle drop and build up the effective suction, in passage 126 to the proper value before the next note is reached.

To vary the intensity of a particular note, it is only necessary to vary the point toward which the plunger and throttle are biased. For doing this automatically under control of the note sheet, I employ a plurality of openings .1 18 in tracker bar 12 connected by suitable control conduits indicated diagrammatically at 148 in Fig. 1. Each conduit 14.8 con'nnunicates with the bottom con trol chamber 150 of a primary control valve, as shown in Fig. 3. .Diaphragm 152 underlies the lower head 154, connected by stem 156 to the upper head 158. From the chamher around the valve S'IBD], the control passage 160 extends to the chamber 162 of the second pneumatic valve as shown in Fig. 4-. The space above the four diaphragms 164; houses the mechanical transmission elements for the expression control, and is in com munication with passageway 126 through the clearance 128 around head 100. Thus, diaphragm 164: is always exposed on its upper surface to the stack suction. In the position shown in Fig. 3, the suction of the source obtains under the diaphragm, being communicated thereto through conduit 16?, and passage 160. lVhen atmospheric pressure is delivered to conduit 1&8 by uncovering the control aperture in the tracker bar, diaphragm 152 will lift the valve, moving head 154: against its seat and lifting head 158. The space under diaphragm 164i is thus connected, to atmosphere through passage 160, and the diaphragm will. rise. Referring now to Figs. 2 and 4, I provide cross pieces 168 guiding vertical pins 170 at their ends,and also operating as stops, for the upward movement of the pins by contact with, the discs 17 2 resting on diaphragms 16 1 and supporting pins 170.

Pivoted at 17%: is a bifurcated lever arm 1T6 normally urged downward by compression spring 178 adjustable from outside by means of set screw 180 threaded through the top cover 82. hen diaphragm 16% is in the lowered position, the downwardly turned toes 162 of lever 17 6 rest on the surface of washer 183. Pin 170 and the diaphragm are thereby relieved of the load of springs 178.

Between the arms of lever 176 is a rocker 18% having its heel positioned over pin 170 and its toe overlying head 100 at 186. Delivery of atmospheric pressure through passage 160 will lift diaphragm 164 and pin 170, tipping rocker 184 about its pintle 1n the free end of lever 176, depressing head 100 and lifting too 182 off body 80. The parts are so proportioned that the power of diaphragm 164; is always sufiicient to move disc 172 against cross piece 168, and the strength and tension of spring 186 is such that head 100 will usually not yield enough to permit toe 182 to remain resting on body 80. l he lift of pin 1T0 thus picks up the rocker 18st and lever 176 so that the effect on the head 100 can be accurately adjusted by means of screw 180 controlling the loading of the leverage.

In the embodimentillustrated, I have shown four different sets of expression biasing mechanism. These may be employed in any number or any sequence. It is customary to adjust them to four different strengths corresponding to four different intensities, but it will be obvious, and is, in fact, also practiced, that two or more of these mechanisms can be actuated simultaneously, particularly when a note or notes is to be struck as loudly as possible immediately after striking one or more notes softly.

In operation, the primary control of the suction in passageway 126 is by means of throttle 92, which will be thrown open to increase the intensity, and closed to decrease the same. In changing rapidly from a very high to a very low Suction, the air delivered to the chambers in the stack by the action of the pneumatics may not be suflicient to cut down the suction soon enough to secure the proper diminished intensity for the next note. In such cases only, the release of the load on head 100 corresponding to the new condition, will let atmospheric valve 108 rise to assist in cutting down the suction at a rapid rate.

Great dii'liculty has been experienced in the past in playing music very softly under automatic control. This is because, when the suction in passage 126 is at or near the minimum suction capable of actuating the pneumatics in the stack to strike an audible note, the striking of several notes simultaneously will decrease this suction to a point where a succeeding note will not be struck at all. It has heretofore been necessary to operate with a wide margin between the mean or average value of suction in passageway 126 and the minimum necessary to strike an audible note. To decrease the margin required and make it possible to play with extreme softness and delicacy, I provide an additional pneumatic 186. Spring 188 adjustably tensioned by screw 190 between bracket 192 on the fixed pneumatic board and the plate 194 on the movable one, normally tends to expand the pneumatic. This tendency is counteracted by the suction in the pneumatic delivered from the stack through conduit 196. Plate 19% extends out at 198 toencircle or straddle the lower end of stem 98. A suitable nut 200 is threaded on this stem. being slotted at 202 and locked by screw 20%. This pneumatic is of considerably greater power than any of the link ages for expression loading, but in ordinary playing it flutters up and down without even establishing connection with the valve. Upon a sudden decrease in suction in passage 126 below a predetermined critical minimum the normal movement of valves 92 and 108 is accelerated by the dropping of plate 19st to strike nut 200 for only a small fraction of instant, the momentary displacement of throttle 92 operating to replace the loss in the stack suction without permanently interfering with the effective control of the same by the other control mechanism atthe upper end of the stem.

VVit-hout further elaboration, the foregoing will so fully explain the gist of my invention, that others may, by applying current knowledge, readily adapt the same for use under various conditions of service. It will, for instance, be obvious that the double control obtained by pneumatic 1S6 isindependent of the nature of the pressure control means for ordinary work and may be applied for various other expression control mechanisms. This and many other adaptations may be made by those skilled in the art without eliminating certain features which may properly be said to constitute the essential items of novelty involved, which items are intended to be defined and secured to me by the following claims.

I claim:

1. In a player piano, the combination with the pneumatic stack, of expression mechanism for varying the suction transmitted to the stack, two independent sources of suction, one motor driven and the other foot actuated, and connections for delivering suction from the motor driven source to the action modified by said expression mechanism and for delivering suction from said foot actuated source to the action direct and unmodified. said connections including separate paths for suction from said sources joining to form a common path, a check valve in the path from the motor driven source to prevent suction from the other source traveling down said path, a pressure sensitive control means for rendering said expression mechanism eifective or by iiassing the same, and a conduit connecting said control means with said motor actuated source.

2. In a player piano, the combination with the pneumatic stack, of expression mechanism for varying the suction transmitted to the stack, two independent sources of suction, one motor driven and the other foot actuated, and connections for delivering suction from the motor driven source to the action modified by said expression mechal5 nism, and delivering suction from said foot actuated source to the action direct and unmodified.

3. In a player piano, the combination with the pneumatic stack, of expression mechanism for varying the suction transmitted to the stack, two independent sources of suction, one motor driven and the other foot actuated, and connections for delivering suction from the motor driven source to the action modified by said expression mechanism and delivering suction from said foot actuated source to the action direct and unmodified, said connections including separate paths for suction from said sources :in joining to form a common path, a check valve in the path from the motor driven source to prevent suction from the other source traveling down said path, a pressure sensitive control means for rendering said 115 expression mechanism eiiect-ive, and a con nection for subjecting said control means to the pressure in said motor actuated source.

In combination, a fixed support, a first floating member having limited movement with respect to said; support, a second floating member, a suction supply conduit in said --sl.ipport, a suction delivery conduit in said sup iort, an atmosphere inlet the clearance between said suppin't and said first floating member determining the efi'ective communication between. said supply and delivery conduits, and the clearance between the first and second floating; members determining the e ibctive communication between said delivery comluit and said atmosphere inlet, contact betwei-en said members enabling the second member to increase the clearance of tile first, and u'ieans yieldably tending to move the first member to closed position, whereby both clearances occur selectively but never at the san'ie time.

5. In combinz-ition, a support, a first floating member having limited movement with respect to said support, a second floating member, a on supply conduit in said ion delivery conduit insaid support, an atn'iosphere inlet the clearance betweensaid support and said first 'fioating' member determining the effective communication between said supply and delivery conduits, and the clearance between said first and second floating members determining the effective communication between said delivery conduit and said atmosphere inlet, contact between said members enabling the second member to increase the clea 'ance of the first, and means yieldably tending to move the first member to closed position, whereby both clearances occur selectively but never at the same time.

6. In combination, a support, a first floating member having limited movement with respect to said support, a second floating member, a suction supply conduit in said support, a suction delivery conduit in said support, the clearance between said support and first floating member determining the effective communication between supply and delivery conduits, and the clearance between said first and second floating members determining the effective communication between said delivery conduit and atmosphere, contact between said members enabling the second member to increase the clearance of the first, and pneumatic means tending to move the first member to closed posit-ion.

7. In combination, a support, a first floating member having limited movement with respect to said support, a second floating member, a suction supply conduit in said support, a suction delivery conduit in said support, and an atmosphere inlet the clearance between said support and said first floating member deteri'i'iining the effective communication between said supply and delivery conduits, and the clearance between said first and said second floating members detern'iining the eiii'ective communication be tween said delivery conduit and said atmosphere inlet, contact between said members enabling the second member to increase the clearance of the first.

8. In combination, asupport, a first menu her having; movement with respect to said :aipport. a second member, a suction supply conduit in said support, a suction delivery conduit in said support, and an atmosphere inlet the clearance between said support and said first member detern'iining the effective communication between said supply and delivery conduits, and the clearance between said first and second members determining the etfective communication between said delivery conduit and said atmosphere inlet, contact between said members enabling the second member to increase the clearance of the 9. In combination, a support, a first memher having movement with respect to said support, a second member, a suction supply conduit in said support, an atmosphere inlet the clearance between said support and said first floating member determining the effective connnunication-between said supply and delivery"conduits, and the clearance between said first and second members determii'iing the eii'ective communication be tween said delivery conduit and said atmosphere inlet, and means yicldably tending to move the first member to closed position.

10. In combination, a support, a first member lmving movement with respect to said support, a second member, a suction supply conduit in said support, an atmosphere inlet a suction delivery conduit in said support, the p sition of said first member determining the eliective communication between said su pl) and delivery conduits, and the clearance between said iirst and second members determining the eiiective communication between said delivery conduit and said atmos phere inlet.

ll. iileans tor operating a player piano mechanism a low pressure comprising, in combination with a pneumatic stack and a source of suction therefore, a valve for maintaining the suction in the stack at a controlled low pressure, a quick acting pressure sensitive means connected to the stack to be actu' atcd by instantaneous variations of pressure therein, and a lost motion connection between said valve and said pressure sensitive means for opening said valve momentarily when the suction in the stack falls below that necessary to operate the action.

12. Means for operating a player piano mechanism low pressures comprising, in combination with apneumatic stack and a source of suction therefore, a valve for maintaining the suction in the stack at a controlled low pressure, a quick acting pressure se sitive means connected to the stack to be actuated by instantaneous variations of pressure therein, and a connection between said valve and said pressure sensitive means for opening said valve.

1?). Means for operating a player piano mechanism at low pressures comprising, in combination with a pneumatic stack and a source of suction therefore, a valve for maintaining the suction in the stack at a controlled low pri sure, a quick acting pressure sensitive means connected to the stack to be actuated by instantaneous variations of pressure therein, and a lost motion connection between said valve and said pressure sensitive means for opening said valve momentarily when the suction in the stack falls below a predetermined value.

l i. In a player piano expression mechanism, in combination, a plunger, a pivoted arm having its free end pivoted to the top of said plunger to support said plunger, resilient means tending to lift said arm and carry the eight of the plunger, av damping piston near the lower end of said plunger, a cylinder for said piston, said piston having light contact with its cylinder walls, said plunger being guided in its movement entirely by said piston and arm,v an axially movable annular throttle encircling said plunger, a chamber housing the outer periphery of said throttle, a source of suction for said chamber, a conduit to the stack leading from one end of said throttle, a seat for the throttle at the end of said conduit cooperating with said throttle to control commui'iication between said chamber and conduit, said throttle normally tending to close itself, the other end of said throttle opening to atmosphere, an atmospheric valve carried by said plunger, an annular seat on said throttle for said atmospheric valve, said valve, when closed, engaging said throttle to operate a mechai'iical connection between said plunger and throttle for opening the throttle, and resilient means controlled by the note sheet for varying the position of said plunger.

15. ln a player piano expression mechanism, in combination, a plunger, a pivoted arm having its tree end pivoted to the top of said plunger to support said plunger, re" silient means tending to lift said arm and carry the weight of the plunger, a damping piston near the lower end of said plunger, av cylinder for said piston, said piston having light contact with its cylinder walls, said plunger being guided in its movement entirely by said piston and arm, an axially movable annular throttle encircling said plunger, a chamber housing the outer periphery of said throttle, a source of suction for said chamber, a conduit to the stack leading from one end of said throttle, a seat for said throttle at the end of said conduit cooperating with said throttle to control connnunication between said chamber and conduit, said throttle normally tending to close itself, the other end of said throttle opening to atmosphere, an atmospheric valve carried by said plunger, an annular seat on said throttle for said atmospheric valvc,said valve, when closed, engaging said throttle to operate as a mechanical connection between said plungcr and throttle for opening the throttle, and resilient means for varying the position of said plunger.

16. In a player piano expression mechanism, in combination, a plunger, a pivoted arm having its free end pivoted to the top of said plunger to support said plunger, resilient n'ieans tending to lift said arn'i and carry the weight of the plunger, a damping piston near the lower end of said plunger, a cylinder for said piston, said piston having light contact with its cylinder walls, said plunger being guided in its movement cntirely by said piston and arm, an axially movable annular throttle encircling said plunger, a chamber housing the outer periphery of said throttle, a source of suction for said chamber, a conduit to the stack leading from one end of said throttle, a seat for the throttle at the end of said conduit Ill) cooperating with said throttle to control communication between said chamber and conduit, said throttle normally tending to close itself, the other end of said throttle opening to atmosphere, an atmospheric valve carried by said plunger, and an annular seat on said throttle for said atn'iospheric valve, said valve, when closed, engaging said throttle to operate as a mechanical connection be tween said plunger and throttle for opening the throttle.

17. In a player piano expression mechanism, in combination, a pneumatic stack, a plunger, a pivoted arm having its free end pivoted to the top of said plunger to sup port said dunger, resilient means tending to lift said arm and carry the weight of the plunger, a damping piston near the lower end of said plunger, a cylinder for said Eaton, said piston having light contact with s cylinder walls, said plunger being guided in its movement entirely by said piston and arm, an axially movable annular throttle emiiii'cliug said plunger, a. chamber housing i outer periphery of said throttle, astmrce or suction for said chamber, a conduit to the stack leading from one end of said thrott e, a seat for the throttle. atthe end of said conduit cooperating with said throttle to control communication between said chamber and conduit, said throttle normally tending to close itself, the other end oi? said throttle opening to atmosphere, a mechanical connection between said plunger and throttle for opening the throttle, and resilient iii-cans controlled by the note sheet for varying the position of said plunger.

18. In a-player piano expression mechanism, in combination, a pneumatic stack, a plnng a pivoted arm having its-free end piv ted to the top oi said plunger to supprnft said plunger, resilient means tendto lift said arm and carry the weight of the plunger, an axially movable annular throttle encirclin said plunger, a chamber housing tie outer periphery ot' said throttle a source of auction for said chamber, a man duit to the stark leading from one end of said throttle, a seat for the throttle at the raid conduit cooperating with said o co= trol comnmnication between said chamber and conduit, said throttle normally tending to c ose itself, the other end of said throttle opening to atmosphere, an atmospheric valve carried by said plunger, an annular seat on said throttle for said valve, said valve engaging said throttle 1 closed to operate as a mechanical con- 7 non between said plunger and throttle for opening the throttle, and resilient means controlled by the note sheet for varying the position of said plunger. I

'19. In a player piano expression mechanism, in combination, a pneumatic stack, a plunger, a pivoted arm havingits 'free'end p l L pivoted to the top of said plunger to sup port said plunger, resilient means ending to lift said arm and carry the weight 01 the plunger, an axially movable annular throttle encircling said plunge a chamber housing the outer periphery of said throttle, a source of suction for said chamber, a conduit to the stack leading from one end of said throttle, a seat for the throttle to con trol communication between said chamber and conduit, said throttle normally tending to close itself, the other end of said throttle :pening to atmosphere, an atmospheric valve carried by said plunger, an annular seat on said throttle i'or said valve, said valve engaging said throttle when closed to operate as a mechanical connection between said plunger and throttle for opening the throttle and. resilient means for varying the position of said plunger.

20. In a player piano expression mechanism, in combination, a pneumatic stack, a plunger, a pivoted arm having its free end pivoted to the top of said plunger to support said plunger, resilient means tending to lift said arm and carry the weight of the plunger, an axially movable annular throttle encircling said plunger, a chamber housing the outer periphery of said throttle, a source of suction for said chamber, a conduit to the stack leading from one end of said throttle, a seat for the throttle at the end of said conduit cooperating with said throttle to control communication between said chamber and conduit, said throttle normally tending to close itself, the other end of said throttle openin to atmosphere, an atmospheric valve carried by said plunger, and an annular seaton said throttle for said valve, said valve engaging said throttle when closed to operate as a mechanical connection between. said plunger and throttle ior opening the throttle.

21. in a player piano expression mechanism, in combination, a pneumatic stack, a ph ger, a pivoted arm having its free end pivoted to the top ct said plunger to support the same, resilient means tendii'ig to lift aid arm and carry the weight of the plunger, an axially movable annular throttle encircling said plunger, a chamber housing the outer periphery of said throttle, a source of suction for said chamber, a conduit leading to the stack from one end of said throttle, a

seat for the throttle at the end of said conduit cooperating with said throttle to con trol con'nnunication bet-ween said chamber and conduit, and a mechanical connection between said plunger and throttle for opening the throttle.

22. In a player piano expression mechanism, in combination, a movable control valve, spring means biasing said valve to apredetermined position, a pluralityof individual and adjustable loading means 'for changing said bias, each loading means comprising a resiliently tensioned linkage, a take-up controlled by the note sheet for moving said linkage into etl'ective connection with said valve, stop means carrying the linkage to relieve the valve when said takeup means is not actuated, and stop means limiting the movement ot said take-up, said take-up being of greater strength than the linkage tension, whereby adjustment of the linkage tension determines the load on said valve.

253. In the player piano expression mechanism. in combination, a movable control. valve. spring means biasing said valve to a predetermined position, a plurality oi individual and adjustable loading means for changing said bias, each loading means comprising a resiliently tensioned linkage, a takeup controlled by the note sheet for moving said linkage into effective connection with said valve, stop means carrying the linkage to relieve the valve when said take up means is not actuated, and stop means limiting the movement of said take-up.

24:. In the player piano expression mechanism, in combination, a movable control valve, spring means biasing said valve to a predetermined position, a plurality of irdividual and adjustable loading means for changing said bias. each loading means comprising a resiliently tensioned linkage, a take-up controlled by the note sheet for moving said linkage into effective connection with said valve, and stop means carrying the linkage to relieve the valve when said takeup means is not actuated.

25. In av player piano expression mechanism, in combination, a movable control valve, spring means biasing said valve to a i redetermined position, a plurality of individual and adjustable loading means for changing said bias, each loading means comprising a resiliently tensioned linkage, and a take-up controlled by the note sheet for moving said linkage into effective connection with said valve.

In a player piano expression mechanism. in combination. a control valve, and loading means for said valve comprising a rocker having one end overlying said valve, a pivoted lever, a pintle for said rocker in the free end of said pivoted lever, pneumatic means under the other end of said rocker tor raising the same, adjustable spring means acting on said lever to move the. rocker against said valve, a stop for the free end of said lever to relieve the valve when said raising means is down, and a stop limiting the raising movement of said raising means but permittitng sufiicient movement to lift said lever off its stop, said raising means be ing more powerful than said spring.

27. In a player piano expression mechanism, in combination, a control valve, and

loading means for said valve comprising .1 rocker having one end overlying said valve, 21 pivoted lever, a pintle for said rocker in the tree end oi said pivoted lever, pneumatic means under the other end of said rocker for raising the same, spring means acting on said lever to move the rocker against said valve, a stop for the free end of said lever to relieve the valve when said raising means is down, and a stop limiting the raising movement of said raising means but permitting sutiicient movement to lift said lever oil its stop.

28. In a player piano expression niechanism, in combination. a control valve. and loading means for said valve comprising a. rocker having one end overlying said valve, :1 pivoted lever, a pintle for said rocker in the free end of: said pivoted lever, pneumatic means under the other end or said rocker :tor raising the same, spring means acting on said lever to move the rocker against said valve, a stop for the free end of said lever to relieve the valve when said raising means is down, and a stop limiting the raising movement of said raising means.

29. In a player piano expression mechanism, in combination, a control alve. and loading means for said valve comprising a rocker having one end overlying said valve, a pivoted lever, a pintle for said rocker in the free end of said pivoted lever, pneumatic means under the other end of said rocker for raising the same, and adjustable spring means acting on said lever to move the rocker against said valve.

30. In a player piano, the combination of a pneumatic stack, a foot operated suction producing source, a motor driven suction producin source, expression mechanism for controlling and modifying the pressure in said stack, and valve mechanism for selectively connecting said expression mechanism for operation with either the foot actuation suction producing source or the motor driven suction producing source. 31. In a player piano, the combination ot a pneumatic stack, a foot operable suction producing source, a. motor driven suction producing source, expression mechanism for controlling the pressure in said stack and in turn controlled by the pressure of said sources, and valve mechanism for connecting for service either one (it said sources with or without the inclusion of the expression mechanism.

32. In a player piano, the combination of the pneumatic stack, a source of suction, a conduit connecting said stack and source, a suction chamber included in said conduit, a throttle valve in said chamber subjected to the suction therein and having a part thereof subjected to atmos 'iheric pressure, said suction and atmosphere pressure cooperating and tending to close said valve ill?) against the force of the valve weight tending to open it, reduction of suction below a certain minimum causing said valve to open by its weight, and controllable means for adding to the weight of said valve whereby said valve may be made to open during suction greater than said minimum.

33. Ina player piano, the combination of a pneumatic stack, a source of suction, a conduit connecting said source with said stack, a suction chamber interposed in said conduit, a throttle valve in said chamber for controlling the flow through said conduit, the suction in said conduit tending to close said throttle valve in opposition to its weight whereby reduction of the suction below a minimum point will result in opening of said valve, and means selectively operable to exert different pressures againstsaid valve to assist its weight in opening the valve during suctions higher than at said minimum point.

34. In a player piano, the combination of a pneumatic stack, a suction producing source, a conduit connecting said source with said stack, a suction chamber in said conduit, a valve in said chamber for controlling the flow therethrough, the suction in said conduit tending to hold said valve closed in opposition to the weight of the valve, said valve tending to open when the suction in said conduit drops below a minimum point, a plurality of pressure devices adapted to exert different degrees of pressure on said valve to assist the valve Weight in overco1ning the suction in said conduit and to open during suction values higher than at said minimum point, and pneumatic means for selecting said pressure devices for operation.

35. In a player piano, the combination of a pneumatic action, a source of suction, a conduit connecting said source with said action, a valve chamber interposed in said conduit, a throttle valve in said chamber for controlling the flow through said conduit and thereby the connection of said action with said source, the suction in said conduit opposing the weight of said valve and causing said valve to open said conduit when the suction in said action reaches a predetermined value, an atmosphere passageway through said throttle valve connected with the action end of said conduit when the throttle valve is closed, an atmosphere valve seating on said throttle valve and normally closing said atmosphere passageway, yieldable means tending to relieve said throttle valve of part of the weight of said atmosphere valve, and pressure means operable to increase the pressure engage ment of said atmosphere valve on said throttle valve whereby to assist the weight of said throttle valve in opening said con duit to increase the suction in said action, and means for controlling the operation of said pressure means.

In witness whereof, I hereunto subscribe my name this 26th day of August, 1924.

WILLIAM L. MORRIS.

CERTIFICATE OF CORRECTION.

Patent No. 1,623,968. Granted April 12, 1927, to

WILLIAM L. MORRIS.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, line 81, claim 6, before the article "the" insert the words "an atmosphere inlet"; line 83, after the word "between" insert the word "said"; line 87, before the word "atmosphere" insert the word "said" and after the word "atmosphere" insert the word "inlet"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed em 24th day of May, A. n. 1927.

M. J, Moore, Sealn Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1,623,968. Granted April 12, 1927, to

WILLIAM L. MORRIS.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, line 81, claim 6, before the article "the" insert the words "an atmosphere inlet"; line 83, after the word "between" insert the word "said"; line 87, before the word "atmosphere" insert the word "said" and after the word "atmosphere" insert the word "inlet"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of May, A. D. 1927.

M. J Moore, Seal, Acting Commissioner of Patents. 

